The present invention relates to a coatings head assembly and method of use. More particularly, the present invention relates to a head assembly for mounting on a specific self-propelled apparatus and is most applicable in removing coatings from large surfaces.
Power washing devices are used to remove coatings and undesirable debris from surfaces as part of routine maintenance and in preparation for application of new coatings. Such power washers are often used to remove coatings such as xe2x80x9cnon-skidxe2x80x9d materials, debris, primers and paints from common substrate materials such as steel, aluminum and concrete. There are numerous well known applications for power washers in manufacture and maintenance of ships, aircraft, automobiles, pipes, buildings, bridges, storage tanks, structures, etc.
In general, power washers are comprised of one or more pumps which supply a fluid, generally water, at high pressure, directed through flow constricting nozzles to the surface to be cleaned. Each nozzle produces a jet of fluid which is guided along the surface to be cleaned. In the prior art, the nozzle is generally mounted to, or part of, a hand held device. In some cases, multiple nozzles are incorporated into manual push xe2x80x9clawn mowerxe2x80x9d type unit and, in some cases, the nozzles are rotated by the force of the jet stream, or by a positively driven spray bar assembly. The advantage of multiple nozzle devices is that larger surface areas can be cleaned more efficiently than with single nozzle devices.
The weight of larger power washing apparatus and/or the thrust produced by larger rotationally driven, multiple nozzle devices precludes utilization in a hand held device. Unsuccessful attempts have been made to attach a power washer to a self-propelled apparatus; known prior art devices either fail in their ability to effectively and efficiently remove coatings and/or lack sufficient containment capabilities.
The effectiveness of power washing apparatus is dependent upon several well known factors. In order to obtain optimum efficiencies, two factors, in addition to operation pressure, are critical. First, the distance from the nozzle(s) to the surface to be cleaned (xe2x80x9cnozzle stand-off distancexe2x80x9d) must be closely controlled. Secondly, the speed at which the nozzles are moved in relation to the surface to be cleaned (xe2x80x9cnozzle pass ratexe2x80x9d) must be closely controlled. Prior art devices are limited in their ability to control the nozzle stand-off distance and/or the nozzle pass rate. The production rate for known prior art power washers is limited to approximately 200 square feet per hour.
Environmental concerns make containment of waste fluid with entrained removed material critical. Prior art devices are limited by their ability to contain the waste fluid and removed material. Containment is equally desired in regard to being able to immediately apply a new coating to the, preferably dry, cleaned surface. Additionally, if fluid remains on steel surfaces, rust will likely form. These factors mandate near 100 per cent containment of the waste fluid and entrained removed material.
There is a need in the art for a coatings removal head assembly with higher associated production rates, improved coatings removal quality, enhanced containment and increased automation. In furtherance of these objectives, there is a need for a device which allows the nozzle stand-off distance and nozzle pass rate to be controlled and automatically adjusted. Additionally, there is a need for a device which provides a means by which a vacuum containment system can be utilized to collect both the coatings, which have been removed, as well as, the waste fluid. The coatings removal head assembly in accordance with the present invention provides the solution to these needs.
The coatings removal head assembly in accordance with the present invention employs a main mounting bracket assembly, for attachment to a self-propelled apparatus. The main mounting bracket assembly incorporates a spring mounting assembly interposed between the main mounting bracket assembly and the coatings removal head housing assembly. The main mounting bracket assembly, combined with the spring mounting assembly, facilitates automatic control of the nozzle stand-off distance. A nozzle stand-off distance between 1 inch and 1.25 inches is typical; with surface irregularities anticipated to exceed this nozzle standoff distance, it is imperative to employ automatic adjustment. The spring mounting assembly provides a durable, effective, automatic adjustment of the nozzle stand-off distance with a minimum number of components. The invention is in no way to be limited to a particular type of spring; any positively loaded spring action device capable of automatic expansion and contraction is within the scope of the present invention.
The coatings removal head assembly of the present invention incorporates a positively driven rotary spray bar assembly which provides improved control over the nozzle pass rate. Rotational rates between 1500-3600 revolutions per minute have been found to be most effective dependant upon the speed of movement of the coatings removal head assembly relative to the surface to be cleaned. However, the invention is in no way limited to any rate of rotation of the rotary spray bar assembly.
It will be obvious to those skilled in the art, that fluid pressure, nozzle characteristics and head assembly cut width (the width covered by one pass of the head assembly) are factors to consider in optimizing the effectiveness of a coatings removal head assembly. It is preferred to operate the coatings removal head assembly in accordance with the present invention with fluid pressure of 40,000 pounds per square inch with a 16 inch cut width. However, the invention is in no way to be limited to any given fluid pressure or cut width.
The coatings removal head assembly of the present invention incorporates an exhaust port, or ports, into the housing assembly designed to attach to a vacuum, whereby the fluid and removed coatings can be collected. The location of the exhaust port(s) in relation to the nozzle(s), as well as the flow capability and characteristics of the exhaust of the coatings removal head assembly of the present invention, provides near 100 percent containment.
There is a further need in the art for a coatings removal head assembly which eliminates the necessity of guiding the head assembly along the surface to be cleaned by means of a hand held or manually-propelled device. There is a further need for a device which allows the spray nozzles to be directed at a surface in any global orientation, whether the surface is vertical, horizontal, overhead or some position there between, while attached to a self-propelled vehicle such as a manlift, powered cart or robot. There is a further need for a device which allows a single operator the ability to simultaneously operate multiple head assemblies.
The main mounting bracket assembly of the coatings removal head assembly in accordance with the present invention facilitates mounting to a self-propelled apparatus. In addition, multiple coatings removal head assemblies in accordance with the present invention may be mounted to one self-propelled apparatus, or multiple self-propelled apparatuses may be employed.
The present invention will be best understood by reference to the following detailed description in light of the accompanying figures and appended claims.